Printing plate clamp



Sept 26, 1933- H. A. w. woon PRINTING PLATE CLAMP originl Filed April 6. 1929 y A C-f-WIM Patented Sept. 26, 1933 A UNITED STATES PATENT OFFICE PRINTING PLATE CLAMP Henry A. Wise Wood, New York, N. Y., assigner to Wood Newspaper Machinery Corporation, New York, N. Y., a corporation of Virginia Original application April 6, 1929, Serial No. 353,201. Divided and this application January 10, 1931. Serial No. 507,833. Renewed January 30, 1933 16 Claims. (Cl. 101-384) This invention relates to a clamp for holding It is the purpose of this invention to provide a plate down on a printing cylinder at the longia clamp which will vhold down this edge of the tudinal edges of the plate. plate which is parallel to the central axis of the The principal objects of the invention are to printing cylinder and to do it in such a manner 5 hold down the straight edges of the plate and that the plate will not be subjected to unnatural 5 prevent their bulging out so as to imprint an exstrains as it grows in length circumferentially cessively black impression on the paper, and also under repeated impressions.

to avoid the possibility of breakage of the edge Referring to Figs. 1, 2 and 3, which are divided of the plate due to its pounding back and forth out of my above identified application, I provide 1 repeatedly, and to provide a construction by each plate 10, in addition to its holding means which when the attendant pulls his end clamps at its semi-circular ends, with a longitudinal retoo tight it will not cause the bo'wing of the edges cess 11 in each straight edge, preferably about of the plate. This case contains matter divided halfway between the ends. 1 also provide marout of my prior application, Serial No. 353,201, gin bars 12 extending along the straight edges of l5 filed April 6, 1929. the plates with two tongues 13 on opposite sides,

Other objects and advantages of the invention each one extending into a longitudinal recess will appear hereinafter. 11 in the plate adjacent thereto and projecting Reference is to be had to the accompanying over a projecting ledge 16 on the plate. It will drawing in which be observed that the bars 12 are of less length 20 Fig. 1 is a plan of a printing cylinder, partly in than the plates and the object of making them 7U section, showing the subject oi this invention; shorter is to permit a pressman to lift the plate Fig. 2 is an enlarged view of the same; by its straight edges which it would be somewhat Fig. 3 is a sectional view on the line 3-3 of diicult to do if such bars were of full length. 1 Fig. 2, and have shown these tongues as of considerable Fig. 4 is a similar transverse sectional view length S0 aS t0 held the plates dOWn and aS having 7 showing a modication. considerable clearance in the recesses at the In clamping stereotype plates on printing press ends. This construction provides the bars with cylinders it is customary to secure them by lonenough Space t0 reeeive and hOld the plates even gitudinal sliding clips carrying` beveled edges to after the plates are lengthened by constant use. t complementary beveled edges on the stereo- These tongues obviously are used in addition to 80 type plates. With slow running presses this form the clamping means and the center clips 14 and of clamping has been sufficient to hold the plates margin rings 15 Ordinarily employed. properly in position, but with the advent of high In Fig. 4 'the invention iS ShOWn in a mOdifled speed printing presses there is a tendency on the form in which the plate 10 iS provided Simply With 35 part of the center of the edge of the plate to bow a longitudinal ledge 16 located in the same posi-y 85 out under speed. The repetition of this action of tion as the recess 11 in the other figures and open pressing the edges of the plates back against the on the outer side, that is, having no metal procylinder as they pass through the impression, jecting over it. As shown in this figure,lthese then throwing them out by centrifugal force, reprojecting ledges will easily slide under the shoulsults in fatigue of the metal and sometimes a ders on the margin bar 19 without any motion 90 piece breaks out of the edge of the plate. This on the part of the plate clamp and thus will reis apt to cause considerable damage. Besides the quire no additional work on the part of the presscentrifugal action just described, the bowing out man in plating up. If necessary the margin bar of the edges of the plates is apt to be caused or can be adjusted by means of its holding screws 5 increased by the setting in of the clamps on both 18 after the plates are in position. 05 ends of the plate.v The natural tendency of a It will be seen that by either of these forms of man working on a high speed press is to keep the invention the diiculties which have been pulling his clamps tighter so that the plate will described above are entirely eliminated. not fly off, thus accentuating the bowing out- Although I have illustrated and described only w wardly o! the edges of the plate. two forms of the invention I am aware of the liv;

fact that other modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be limited to the exact form of construction shown herein but what I claim iszi 1. The combination with a printing plate cylinder, of a margin bar extending longitudinally thereof and having tongues projecting on opposite sides. a printing plate on each side thereof, each printing plate having a longitudinal recess in its straight edge into which said tongues are adapted to project to hold the straight edges of the printing plates down on the cylinder and means for clamping the curved edges of the plates on the cylinder.

2. As an article of manufacture, a printing plate cylinder for mounting substantially semicylindrical stereotype printing plates, said cylinder having means rigid with the cylinder for holding down the straight edges of a printing plate, said means providing circumferential clearance between the plate and said means, and means for clamping the curved edges of the plate.

3. As an article of manufacture, a printing plate cylinder for mounting substantially semicylindrical stereotype printing plates, said cylinder having rigidly secured thereto means for holding down on the cylinder the straight edges of a printing plate, said means providing clearance between the plate and said means, and axially movable means for clamping the curvededges of the plate.

inder adapted to carry a plurality of substantially semi-cylindrical stereotype printing plates, of plate-restraining means for preventing the bowing, of the plates along their straight edges, said means providing circumferential clearance between the plate and said means, and means for clamping the curved edges of the plates.

5. The combination of a substantially semicylindrical stereotype printing plate having a ledge along the inner portion of its straight edge, and a plate cylinder, a margin bar rigidly secured to said plate cylinder having a tongue provided with an inner substantially tangential surface projecting over the printing plate ledge and thereby holding the straight edge of the plate against the cylinder, said bar providing clearance between the plate and bar, with means for clamping the curved edges of the plate 6. The combination with a printing plate cylinder, of a margin bar extending longitudinally thereof and having projections on opposite sides, a substantially semi-cylindrical stereotype printing plate on each side thereof, each printing plate having substantially tangential ledges along its straight edges over which the said projections are adapted to project to restrain bowing of the plates while running, said ledges providing circumferential clearance between the plate and ledges, and means for clamping the curved edges of the plate on the cylinder.

7. The combination with a printing plate cylinder, of a margin bar extending longitudinally thereof and having a substantially tangential projection on its side, a substantially semi-cylindrical stereotype printing plate having a ledge along its straight edge, over which the projection is adapted to project to restrain bowing of the plate while running, said ledge providing circumferential clearance between the plate and ledge, and means for clamping the curved edges of the plate on the cylinder.

8. The combination with a printing plate cylinder adapted to carry a substantially semi-cylindrical stereotype printing plate of insufficient strength to prevent the straight edges thereof from leaving the cylinder when rotated at printing speed, of means rigid with the cylinder for restraining the straight edges from leaving the cylinder, said means providing circumferential clearance between the plate and said means.

, 9. In a printing plate cylinder'adapted to carry a substantially semi-cylindrical stereotype printing plate having insufficient strength when rotated at printing speed to prevent its straight edges from bowing, the combination of end clamps for clamping the curved edges of the plate to the cylinder and restraining means rigid with the cylinder contacting with the tangential surfaces only on the straight edges of the plate to prevent them from bowing when the said cylinder is in operation.

10. The combination of a printing press cylinder adapted to carry substantially semi-cylindrical stereotype printing plates at high speed wherein the curved edges of the plate are clamped to the cylinder by means of clamps whose clamping force is applied to the plate in a direction which tends to buckle the straight edges of the plate, and means carried by the cylinder for restraining the straight edges of the plate from` buckling, said means contacting with the tangnttial surfaces only on the straight edges of the p a e.

11. rlhe combination of a printing press cylinder adapted to carry substantially semi-cylindrical stereotypev printing plates at high speed, and clamps for clamping the curved edges of the plate to the cylinder whose clamping force is applied to the plate in a direction which tends to buckle the straight edges of the plate, of projecting means carried by the cylinder under which projections on the straight edges of the plate are slipped when the plate is placed upon the cylinder, the said projections serving to restrain the straight edges of the plate from buckling, said l'120 means providing circumferential clearance between the plate and said means.

12. The combination with a printing press cylinder adapted to carry substantially semi-cylindrical stereotype printing plates at high speed, and clamps for clamping the curved edges of the plates to the cylinder Whose clamping force is applied to the plate in a direction which tends to buckle thel straight edges of the plate, of fixed projecting means carried by the cylinder for restrainingthe straight edges of the plate from buckling, said means providing clearance between the plate and said means.

13. 'Ihe combination with a cylinder adapted to carry substantially semi-cylindrical stereotype 186 printing plates, of lclamps for the straight edges of said printing plates adapted to restrain the said straight edges from leaving the cylinder by centrifugal force, said clamps being so positioned on said cylinder that projections on the straight; 140 edges of the plate will pass beneath the clamps for the straight edges when the plate is placed upon the cylinder, said clamps providing circumferential clearance between the plate andthe clamps, and means for clamping the curved edges 45 of the plate.

14. The combination with a. printing plate cylinder, of a margin bar thereon extending longitudinally and having tongues projecting on opposite 150 sides, a printing plate on each side thereof, each 16. As an 4article of manufacture. a printing plate cylinder for mounting substantially semicylindrical stereotype printing plates, said cylinder having means for clamping the curved edges of the plate and means rigid with the cylinder and of less than plate width for holding down the straight edge oi the plate.

HENRY A. WISE WOOD.

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